diff --git a/js/bootstrap-formhelpers-number.js b/js/bootstrap-formhelpers-number.js
index 1aa5c6a..eb6e0d4 100644
--- a/js/bootstrap-formhelpers-number.js
+++ b/js/bootstrap-formhelpers-number.js
@@ -166,7 +166,12 @@
       
       value = this.getValue();
       
-      value = value + 1;
+      if(this.options.step === undefined){
+        value = value + 1;
+      }
+      else{ // if use has specified 'data-step' attribute in <input> tag
+        value = value + this.options.step;
+      }
       
       this.$element.val(value).change();
     },
@@ -176,7 +181,12 @@
       
       value = this.getValue();
       
-      value = value - 1;
+      if(this.options.step === undefined){
+        value = value - 1;
+      }
+      else{ // if use has specified 'data-step' attribute in <input> tag
+        value = value - this.options.step;
+      }
       
       this.$element.val(value).change();
     },